Process for producing carbids of silicon and by-products.



TED STATES PATENT OFFICE.

SAMUEL PEACOCK, OF CHICAGO, ILLINOIS, ASSIGNOR, BY MESNE ASSIGNMENTS, T0 AGRICULTURAL RESEARCH CORPORATION, OF NEW YORK, N. Y., A CORPORATION OF NEW YORK.

PROCESS FOR PRODUCING CARBIDS OF SILICON AND BY-PRODUCTS.

No Drawing.

To all whom it may concern Be it known that I, SAMUEL PEACOOK, a citizen of the United States, residing at Chicago, in the county of Cook and State of Illinois, have invented certain new and useful Improvements in Processes for Producing Carbids of Silicon and By-Products; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertaim to make and use the same.

This invention relates to a process for producing carbids of silicon, aluminum and potassium from a mixture of feldspar and carbon, and has for its object the manufacture of carborundum, as well as other products in an eflicient and expeditious manner.

To these ends the invention consists in the novel procedure constituting my invention all as will be more fullv hereinafter disdisclosed and particularly pointed out in the claims.

In carrying out my invention, I provide a finely divided mixture of carbon, preferably in the form of coke, and feldspar, or leucite, or other suitable material, and so proportion the constituents that for each pound of silica present, there will be substantially eight tenths (.8) of a pound of carbon, while for each pound of alumina present, there will be substantially (.75) seventy-five hundredths of a pound of carbon, and for each pound of potash present,

there will be substantially (.3) three tenths of a pound of carbon. This mixture is charged into a suitable air-tight electric furnace provided with an air pump adapted to maintain the pressure in said furnace at about three fourths of an atmosphere or lower. The temperature is next raised to about 2000 C. whereupon the carbids of aluminum and potassium that have been formed will be in a state of volatilization, and will be drawn off by said pump. The temperature is next further raised to substantially 2400 C. if it is desired to form siloxicon Si C O, and higher to say substantially 3300- or3500 C. or higher in order to form carborundum SiC.

The carbids of aluminum and potassium may be collected in a suitable bag separator; or if desired they may be burned to alumina Specification of Letters Patent.

Application filed July 17, 1912.

Patented Mar. 30, 1915.

Serial No. 710,099.

and to potassium carbonate by passing them through a combustion chamber with an excess of air.

From the foregoing it will be observed that by substituting feldspar for sand as the raw material in making carborundum or s1lox1con, I am enabled to utilize the high temperatures required to recover aluminum and potash compounds as by-products, the value of which greatly exceed the additional cost involved.

By pumping out thefurnace and thereby dlmmlshmg the partial pressures of the products of the reaction, I am enabled to produce the above carbids at lower temperatures than would otherwise be possible, and further the carbids of aluminum and potassium are not so liable to dissociate in the furnace after they have been formed. This also is true of siloxicon, which in the presence of ainwill dissociate at about 27 00 C.

When 1t is desired to form siloxicon, apart from the three carbids above, the constitucuts of the charge are proportioned accordlngly.

What I claim is 1. The process of making a compound contammg SlllCOIl and carbon and recover mg aluminum and potassium compounds which consists in heating a mixture of carbon and it finely divided mineral containing s1l1con, aluminum and potassium to a temperature suflicient to produce aluminum and potassium carbids; pumping oif said carbids from the sphere of the reaction; and then further heating the residue until said silicon compound is formed, substantially as descrlbed.

2. The process of making a compound contammg sllicon and carbon and recovermg aluminum and potassium compounds wh1ch consists in heating under a pressure less than that of the atmosphere 9 mixture of carbon and a finely divided mineral contaming sillcon, aluminum and potassium, to a temperature suflicient to produce aluminum and potassium carbids; removing said carblds from the sphere of the reaction thereby lowering the partial pressures of the reaction products; and then further he iting the residue until said silicon compound is formed, substantially as described.

3. The process of making carborundum and by-products fromfeldspar whichconsists in heating, under a pressure less than that of the atmosphere, a charge of finely divided feldspar and carbon to a temperature sufliclent to form carbids of aluminum and potassium; removing said carbids from the charge and thereby lowering the partial pressures of the reaction products; then raising the temperature to a point suflicient to form the carborundum, substantially as described. 1

4. The process of making carborundum and by roducts from feldspar which con sists in' eating, under a pressure less than that of the atmosphere, a charge of finely divided feldspar and carbon to a temperature sufficient to form carbids of aluminum and potassium; removing said carbids from the charge; then raisin the temperature to a point sufiicient to orm slloxicon; and finally raising the temperature to a point I sufiicient to form the carborundum, substantially as described.

5. The process of making carborundunr and by-products from feldspar which consists in heating, under a pressure .less than that of the atmosphere, a charge offinely divided feldspar and carbon to a temperature sufiicient to form carbids of aluminum and potassium; removing said carbidstfrom the chargeand burning them in an excess of air to form oxygen compounds of said metals; then raising the temperature to a point suflicient to for tially as desri ed.

In testimony whereof, I afiix my'signature, in presence of two witnesses. Y

SAMUEL PEAGOCK.

Witnesses:

T. A. WrrHERsPooN, N. CURTIS LAMMoNn.

the carborundum, substan- 

